When an automatic start system is added to a manual start system for a gas turbine engine, special considerations are necessary in order to minimize potentially dangerous situations both to operating personnel and to the turbine engine itself. These include, but are not limited to, damage or unnecessary inspection of the turbine engine due to incompatible operation between the automatic and manual systems; the loss of the ability to shutdown or manually continue to start the turbine engine after an unsuccessful automatic start attempt; occurrence of dangerous situations to operating personnel due to incompatible operation of the automatic and manual systems.
There have been no known prior attempts to solve this problem, partially because prior efforts on gas turbine automatic start systems did not include considerations of erroneous operation between automatic and manual systems. U.S. Pat. No. 2,866,385, granted to Miller, K. W., is an automatic start system employing stepper motor relays for use on an unmanned vehicle. Due to the nature of the stepper relays, it is not obvious what consequences will result if an automatic start sequence is interrupted and then re-initiated. U.S. Pat. No. 3,310,937, granted to Smith, E. G., is an autostart system using fixed solid state circuitry for timing and sequencing control. It does not address operational problems which might damage an engine.